Apparatus for administering anaesthetic gases



Dec. 29 1925- 1,567,868 H. W. C. SCHRUl DER APPARATUS FOR ADMINISTERING ANESTHETIC GASES Filed August 14, -l925 5/ i B N L r tom/vats Patented Dec; 29, 1925.

UNITED STATES PATENT OFFICE.

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APPARATUS FOR ADMDIISTERING ANESTHETIG GASES.

Application filed August 14, 1925. Serial No. 50,311.

To all whom it may concern:

Be it known that I, HANs WILHELM CHRISTIAN Sormtinnn, a German citizen, residing at Lubeck, Germany, have invented certain new and useful Improvements in Apparatus for Administering Anaesthetic Gases, of which the following is a. specification.

The invention relates to an improved method of and apparatus for administering gases and the like, particularly in simultaneously administering two or more different gases and the like. 7

In the well known method of and apparatus for the inhalation of two different gases, vapor or the like for the purposes of therapeutical or clinical treatment, for instance of a nutrient gas and of a gaseous anaesthetic, the quantity of gas required for satisfying the requirement of breathing during the whole time of treatment, as well as the anaesthetic, were taken from storage containers and supplied to the patient in a continuous manner, whilst maintaining the proportion of the as mixture required to ensure anaesthesia, or instance of 50% nutrient gas and 50% gaseous anaesthetic. This means however a badutilization of the existing stock of gas, more particularly a waste of the expensive anaesthetic. Moreover other persons in the room are greatly inconvenienced by the gases which the body of the patient fails to absorb.-

The present invention aims at eliminating the drawbacks above referred to. This is done by providin mixing chamber an in the tube, a stock of gas suiiicient for a deep respiration, which is alternately inhaled and exhaled out whilst the quantity of nutrient gas required for the'life processes, is supplied in a continuous current. On the contra the supply of the therapeuticall or clinically ae tive gas is entirely or part y cut off after the saturation of the blood has taken lace. In order to overcome a difiiculty whic is more particularly felt by beginners, namely that of correctly measuring by the depth of respiration, the gas quantity required, it is advisable at the beginnin of the treatment to. supply ample gas an to discharge the small excess outwards through a spring or throttle valve provided in the exhaling tube.

This has the advantage that not only no de-' pressure gauge e.

from the first in the.

ficiency of gas occurs, but that a uniform pressure is ensured 1n the gas circulation system, and that the proportion of mixtureoi gases can be maintained more accurately with a small excess of supply over the consumption.

A construction of the apparatus for car 5 a gaseous anaesthetic (laughing gas,- car-' bonic acid, acetylene etc.). By means of the dosing pressure reducing valve 0, a given oxygen current consumed by breathing (in -the case of grown up persons about 1.5 liter 'per minute) is set, by adjusting in the usual manner the set screw 0? and reading on the The current of gaseous anaesthetic is first set at the dosing pressure reducing valve f to the amount required to produce a given depth of anaesthesia, and later on throttler-or shut ea, also by operating a set screw 9 and observing the pressure gauge 72.. Instead of combining the pressure reduction and gas dosing in one valve 6, 1, separate fittings could be provided for each operation.

The nutrient gas passes to the storage bag m through the tube or. pipe 2', and the gaseous anaesthetic through the pipe in. The storage bagin inflated state must be so large as to be able to supply a powerful lung with gas in the case of a. deep inhalation, or receive all the gas exhaled in the case of a deep exhalation (about 5 liters). The patient inhales the gas mixture from the bag at through the check valve a, tube a and the face mask .32. The bag becomesthen for the most port emptied as it receives from the pipesi and It only a slight additional supply of gas; at the end of the exhalation stage, it will be however completely filled again, as the exhaled air will be returned to the bag m through the tube 9, check valve 1', three way cock a, pipe a, chemical container t and pipe '2), or the three way cock 8, pipe u and pipe 41. The quantity of the gas exhaled is reduced only: firstly by the amount of the nutrient gas consumed in the body of the patient, about 5% of the quantity inhaled, and secondly by the quantity of gaseous anaesthetic required for a given degree of saturation, which again amounts only to a portion of the above 5%, and eventually can sink to In the chemical container 25, the air exhaled is freed from carbonic acid. If however the carbonic acid is not to be removed, or to be only partly removed, in order to have a stimulant for the breathing centre in the case of an insufiiciently strong respiration, the admission to the chemical container is partly or entirely closed by means of the three Way cock 5, and instead, the admission to the by-pass w is opened. In ororder to attain a more accurate addition of carbonic acid, the carbonic acid exhaled must be completely absorbed, and fresh carbonic acid supplied to the storage bag in they same way as the other two gases by means of a dosing valve.

If owingto an excessive supply of gas, a certain excess of pressure is produced in the exhalation pipe, it is discharged, according to the invention, into the atmosphere through an excess relief valve. In the construction illustrated, such an adjustable and automatically acting relief valve w Which could be made for instance in the form of a spring controlled or throttle valve, is provided in the return piping section a, preferably in a branch w of the same, which could be further provided also with a cock as.

I claim:

1. In an apparatus for administering anaesthetic gases by inhalation, the combination of a mixing chamber for containing a mixture of said gases,-an inhalation pipe, a bifurcated exhalation pipe having two branches leading to said mixing chamber, a carbonic acid absorption device in one of said branches, and a three-way cock in said exhalation pipe whereby exhaled air is conveyed back to the mixing chamber at will through one or the other of said branches or through both branches simultaneously.

2. In an apparatus for administering anaesthetic gases by inhalation, the combination of a mixing chamber for containing a menses mixture of said gases, an inhalation pipe, a bifurcated exhalation pipe having two branches leading to said mixing chamber,

a carbonic acid absorptiondevice in one of said branches, and a three-way cock in said exhalation pipe whereby exhaled air is conveyed back to the mixing chamber at will through one or the other of said branches or through both branches simultaneously, and an automatically acting relief valve in said exhalation pipe in communication with. both branches thereof whereby excess gaseous fluid is automatically discharged.

3. In an apparatus for administering anaesthetic gases by inhalation, the-combination of a-mixing'chamber for containing a mixture of said gases, an inhalation pipe, a bifurcated exhalation pipe having two branches leading to said mixing chamber, a carbonic acid absorption device in one of said branches, a check valve in each of said inhalation and exhalation pipes, and a threeway cock in said exhalation pipes whereby exhaled air is conveyed back to the mixing chamber at will through one or the other of said branches or through both branches simultaneously.

4. In an apparatus for administering anzesthetic gases by inhalation, the combination of a mixing chamber for containing a mixture of said gases, an inhalation pipe, a bifurcated exhalation pipe having two branches leading to said mixing chamber, a carbonic acid absorption devicein one of said branches, a check valve in each of said inhalation and exhalation pipes, and a threeway cock in said exhalation pipes whereby exhaled air is conveyed back to the mixing chamber at will through oneor the other of said branches or through both branches simultaneously, and an automatically acting relief valve in said exhalation pipe in communication withboth branches thereof, whereby excess gaseous fluid is automatically discharged.

HAlxlS WlLHELlll QHEHS'H'IAN SCEillilDEli. 

